Process for breaking petroleum emulsions



m. Drawing.

. Patented Apr. 14, 1931 UNITED 4 STATES PATENT; OFFICE JULIUS ANDARTHUR F. SGHLANDT, CHICAGO, ILLINOIS, ASSIGNOBS IO THE PURE COMPANY, OFCHICAGO, ILLINOIS, A CORPORATION OF OHIO PROCESS FOR BREAKING PETBOLEUImil-810KB This invention relates to an improved process for breakingpetroleum emulsions for the purpose of separating effectively andeconomically the oil content of the emulsion and g to render suchoilsuitable for commercial purposes. Petroleum emulsions of the characterreferred to are frequently found in the crude oils pumped from wellsand, again the emulsions are found in the bottoms 0 tical manner.

oil storage tanks or in other receptacles in which crude oil especiallyis allowed to stand. These emulsions contain varying amounts of oil,water or brine and other foreign matter and are of a relatively stablecharacter, being difficult to break down and separate into componentparts in an economical and prac- The emulsions are known in the industryby a variety of names and are frequently referred to as cut oil, roilyoilf basiso sediment, bottom settlings, sludge an B.

It is a principal object of the present invention to treat etroleumemulsions of this type in an efi'ectlve manner whereby to de-.

stroy the permanency or stability of the emulsion and cause it to breakor separate promptly in order to yield separate strata of oil and wateror other foreign substances,

V form insoluble compounds, then droplets ofacidified water suspended inthe oil will, according to our hypothesis, carry smaller positivecharges than do pure water droplets of'the same size, whereas dropletsof basic water will carry larger positive charges.

Certain investigators have found, however, that water droplets suspendedin crude petroleumoils in the form of oil-field emulsions migrate, underthe influence of a strong electrical field, either to the positive ornegative ole of said field. They. have determined, rthermore, that whenthe water is acid the whereby. the oil ma be separately collected andreplaced to various commercial apnea... mm me to, is. we Io. $50,128.

diipiplets migrate toward the negative pole, w mi ate toward thepositive ole.

11 order to harmonize our othesis with the results of investi ationprevlously stated, we further assume th in oil-field emulsions containsacld bodies which are capable of combinin with alkaline earth ions toform insolub e compounds.

Such an assumption has considerable experimental basls, and representsin art the res ent-day attitude toward oil-fie d emulsions. Acid bodiesof the type designated are grouped to ether under the name naphthemcacids Water-insoluble organic acid salts are said to be ne atively chared in collodial condition, an are lyopholfic in character that is, theytend to flocculate or otherwise precipitate from aqueous solutions. Whensoa is placed in hard water, the scum whic is formed is a good exampleof a water-insoluble organic acid salt. Because of the comparative lowacidity of the naphthenic acids, their water-insoluble salts cannotexist in contact with fairly strong acid waters. Hence, such acid-watersin emulsion form will carry their naturalpositivecharge (even though notso ronouncedly as would neutral waters), and in an electric field willmi ate toward the negative nole. If the water 1n oil-field emulsions isalka 'ne, however, the water droplets are covered with an insoluble scumof naphthenic acid metal- -lic salts, bearing the opposite charge tothat of the alkaline water. The result is that the system alkaline water"and scum carries a capillary negative charge, and moves toward e whenthe water is alkaline the droplets at the crude petroleum The first ofthese steps may be carried out in a variety of ways, as for example, bythe addition of inorganic acids, which liberate the naphthenic acidsfrom their salts; or by the addition of alkali metal salts of organicacids capable of forming soluble compounds with calcium and magnesium,in which instance the lyophilic naphthenic acid salts of the alkalis areformed by double decomposition. For instance, the calcium and magnesiumsalts of many sulfonated fatty and naphthenic acids do not form a scumin water, but appear to be soluble. They are in reality lyophiliccolloids. Hence, if a sodium salt of a sulphonated fatty or naphthenicacid is added to the lyophobic calcium or magnesium naphthenate, therewill be formed by double decomposition, say, calcium sulfo-naphthenateand sodium naphthenate, both of which are lyophilic.

The second step is more difficult, in view of the fact thatcomparatively few of the lyophilic negative colloids are oil-soluble. Asoil-field emulsions are all of the waterin-oil type, the water is thedisperse phase, the oil the continuous phase. Hence, to reach the water,the colloid must first traverse the intervening oil.

We have found that it is possible to combine both steps describedpreviously by allowing the lyophilic negative colloids to be formeddirectly in the body of the emulsion, preferably within or at thesurface of the water droplets, where at least one of the reactingsubstances or at least one of the reaction products isan acid.

Examples follow:

Sulfur dioxide and hydrogen sulfide react to give sulfur and water.Sulfur thus formed is a lyophilic negative colloid, the sulfur dioxidebeing the acid. In an actual test, a very tenacious oil-field emulsioncontaining between 40- and 50% of B. S. &W. was treated for about oneminute with sulfur dioxide, by allowing the sulfur dioxide gas to bubblethrough the emulsion inclosed in a container. Thereupon the emulsion andas were agitated vigorously by shaking, a ter which the emulsion wasagain similarly treated with hydrogen sulfide gas and received a similarshaking. An action became apparent im mediately, and after the containerand its contents had been heated to 130 F. for ap proximately 90 minutesthe separation of oil from water and scum was practically completed.

When sulfur chloride is mixed with water, sulfur and hydrogen chlorideare among the products formed. Here, too, some of the sudfur formed actsas a lyophilic negative colloid, the hydrogen chloride being the acid.

In an actual test, the equivalent amount of two pounds sulfur chlorideper hundred barrels emulsion was mixed with a very stable emulsioncontaining about 5% B. S. & W.

accuser (We have found it advantageous at times to dilute the sulfurchloride by mixing it with an inert petroleum fraction or crude.) In 2-lhours there had been practically a complete separation of water fromoil, the tempera ture having been held at 145 F. A blank under the sameconditions still showed almost 4% of water remaining in the oil.

Similarly, silicon tetrachloride, which reacts with the water to givesilicon dioxide (:1 lyophilic negative colloid) and hydrogen chloride,has been found. effective in break ing certain emulsions. Also, sulfurdioxide alone and hydrogen sulfide alone are able 'tobreak someemulsions. We ascribe this action not only to the acid properties ofthese gases, but to the probability that they react with certainconstituents of emulsions to produce colloidal sulfur.

Chlorine gas is efficacious in breaking certain emulsions. lVe believethat the hypochlorous acid formed by the action of chlorine on Waterattacks certain of the sulfur compounds present in the emulsion to givecolloidal sulfur and'hydrochloric acid, and that the action is notWholly due to the acid present.

However, we find that oil-soluble inorganic acids, such as sulfurdioxide and hydrogen chloride, may in some cases bring an emulsion toa-form where heat alone will cause it to break. We find, in general,that small quantities of such strong oil-soluble inorganic acids ashydrogen chloride tend to separate the water droplets and scum togetherfrom the body of oil in an oil-field emulsion, leaving the supernatantoil quite clear.

It will be understood that the amounts of reagents emplo ed in relationto the quantity of oil treated 13 determined largely by the specificcharacter of the emulsion undergoing treatment. In general, however,we'findit advantageous to use reagents which react with the Water in theemulsions only when the water content is comparatively low, this limitbeing determined by the treating costs.

What is claimed is:

l. A process for breaking opietroleum efnulsions, which consists. inintro ucing intosuch an emulsion acid anhydrades in the form of surphurdioxide and hydrogen sulfide which react directly in the body of theemulsion to form lyophilic negative colloids, and then heating theemulsion and allowing it to stand f until the separation of the oil andthe waterlike constituents thereof takes place.

3. A process for breaking oil and water petroleum emulsions, whichconsists in introducing into such an emulsion two or more gases whichreact in the emulsion to form an acid and lyophilic negative colloids,the acid liberated serving to remove or dissolve the water-insolublenaphthenic acid salts surrounding the water droplets contained in theemulsion to remove the negative colloids to contact directly with thewater-dro lets to neutralize the positive charge on sue droplets, andsubsequently removing the oil from the separated water. 7

4. A process for breaking petroleum emulsions, which consists inpermeating such an emulsion with sulphur dioxide and in subsequentlythoroughly permeating the emulsion with hydrogen sulfide whereby todevelop directly in said emulsions by the interaction of said gasesacids and lyophilic negative 001- loids.

5. The method of breaking oil and water petroleum emulsions wherein thewater droplets in such an emulsion are in the dispersed phase andencased in water insoluble na hthenic acid salts, the oil of theemulsion ing in the continuous phase which consists in releasing withinsuch an emulsion by the addition of extraneous com ounds thereto aninorganic acid capable o removing or dis solving the covering of waterinsoluble naphthenic acid salts surrounding the positively chargedwater-droplets and developing and thereby bringing into direct contactwith such droplets lyophilic colloids bearing a negative charge capableof neutralizing the positive charge on the water droplets.

6. Themethod of breaking oil and water petroleum emulsions wherein thewater droplets in such an emulsion are in the dispersed phase andencased in water insoluble naphthenic acid salts, the oil of theemulsion being in the continuous phase, which consists in releasingwithin such an emulsion by the addition of extraneous com unds theretoan.

inorganiciacid capable o removing or dissolving the covering of waterinsoluble naphthenic acid salts surrounding the positively charged waterdroplets and developing and thereby bringing into direct contact withsuch droplets lyophilic colloids bearing a negative charge capable ofneutralizing the positive charge on the water droplets, and permittingthe emulsion to stand until the complete separation of the water fromthe oil constituents thereof is efiected.

7. The method of breaking oil and water petroleum emulsions wherein thewater droplets in such an emulsion are in the dispersed phase andencased in water insoluble napht-henic acid salts, the oilof theemulsion being in the continuous phase, which consists in releasingWithin such an emulsion by the addition of extraneous compounds theretoan inorganic acid capable of removing or dissolving the covering ofwater insoluble naphthenic acid salts surrounding the positively ybringing lnto direct contact with

